The present invention relates to a memory card including an IC (Integrated Circuit) chip.
Conventionally known is a memory card with an IC chip therein, which starts to operate in response to an external input signal, compares the input signal with identification information previously stored in the chip, and delivers a comparison result.
Disclosed in U.S. Pat. No. 4,483,067 (by Parmentier) is a method for manufacturing an identification card of a type which is so constructed that a secondary carrier, on which an IC chip is mounted, is provided in a primary carrier, which is formed of a number of sheets of an electrically insulating thermoplastic material.
U.S. Pat. No. 4,222,516 (by Badet et al.) also discloses an identification card which is formed of only a single sheet.
Using the prior art identification cards, the inventor studied on the prevention of breakage of IC chips, and the maintenance of the reliability of electrical conduction of contacts, for external connection. Thereupon, the identification card provided by the method of Parmentier was founded to be preferable to the card by Badet et al.
It was revealed, however, that the former identification card, using a primary carrier formed of a number of laminated sheets, still involves a problem. Namely, the primary carrier is liable to warp, due to changes in ambient temperature or humidity, while an adhesive agent for lamination is being dried, and after the lamination. In other words, the card is prone to warpage.